Thus, for a given 3-body DA, \(\phi _{3\pi }\) , the 2-body twist-3 DAs are uniquely fixed. Since we started
from a truncated expansion of \(\phi _{3\pi }\)  we arrive at truncated Gegenbauer expansions of the 2-body
twist-3 DAs [1]} (the \(C_n^m\)  denote the Gegenbauer polynomials):
\(\phi _{\pi p}(\tau )&=& 1+\frac{1}{7}\frac{f_{3\pi }}{f_\pi \mu _\pi }\Big ( 7\,\omega _{1,0}- 2\,\omega _{2,0}-\omega _{1,1}\Big ) \nonumber \\&& \hspace*{42.7026pt} \times \; \Big ( 10\, C_2^{1/2}(2\tau -1) - 3\,C_4^{1/2}(2\tau -1)\Big )\,.\) 
